Fig. 5: Chemogenetic inhibition of DRN GABAergic neurons produced a win in both the tube test and the warm spot test.
From: GABAergic neurons in the dorsal raphe nucleus regulate social hierarchy in mice
a Schematic representation of the injection site in the DRN for the virus AAV2/9-GAD67-hM4D(Gi)-mCherry-WPREs. b Representative photomicrographs of the DRN depicting hM4Di (red, left) with the enlarged pictures for the boxed area showing hM4Di expression (red, second subplot), GAD67+ (green, third subplot), and their co-localization with DAPI (right). c Example of the ranking positions of a cohort of mice tested daily over 7 days, demonstrating that the last-ranked mouse injected with the hM4Di virus ascended to third place following CNO administration. d Summary of rank changes in DRN-hM4Di mice before and after CNO injection. Each line represents an individual animal. e Statistical analysis of mean rank change in DRN-hM4Di mice following CNO injection at 0 h (Wilcoxon Signed Rank Test; at 3-5 h: Z6 = -2.530, p = 0.011; at 6-8 h: Z6 = -2.070, p = 0.038). f Behavioral annotations of two tube test trials between the same pair of mice before and after CNO injection. g Chemogenetic inhibition of DRN GABAergic neurons significantly increased the number (Mann-Whitney U-test: U = 64.5, p < 0.001) and duration (U = 41.5, p < 0.001) of push-initiation, the number (U = 84, p < 0.001) and duration (U = 84, p < 0.001) of push-back, the percentage of time spent in resistance (U = 51, p < 0.001), and the number (U = 117, p = 0.011) but not the duration (U = 135, p = 0.050) of stillness. Moreover, the percentage of time spent in retreat was significantly decreased by chemogenetic inhibition (U = 18, p < 0.001). “n” refers to the number of occurrences of the specific fine behaviors being measured. h Duration of occupying the warm spot (left; one-way repeated measures ANOVA with Bonferroni correction: F2,14 = 0.769; p = 0.482; n = 8) and rank in the warm spot test (right; Friedman test with Wilcoxon signed-rank test for multiple comparison: χ2 = 0; p = 1; n = 8) for DRN-hM4Di mice assessed at 1 day before, 2 h after, and 2 days after saline injection. Each gray folded line represents an individual animal, while the colored line represents the average. Mice with the same rank are arranged in parallel to facilitate result presentation. i Duration of occupying the warm spot (left; F2,12 = 20.018; p < 0.001; n = 7) and rank in the warm spot test (right; χ2 = 9.579; p = 0.008; n = 7) for DRN-hM4Di mice at 1 day before, 2 h after, and 2 days after CNO injection. *p < 0.05, **p < 0.01, ***p < 0.001.
